ACADEMY OP NATURAL SCIENCES. 59 



tentacles are conical and acute. The branchial orifice does not present the pecu- 

 liar characters of Actinocyclus. Although all these species differ to some extent, 

 they have no characters to distinguish them generically from the typical Doris, 

 unless anatomical or microscopical examination should reveal them, or the 

 characters of that genus should be more closely limited. 



Triopa Johnston, 1838. 

 T. catalinm Cooper. State coll. species, 1002. 



Form much elongated, narrow, dorsal surface flat, becoming spatulate poste- 

 riorly. Head expanded laterally and flattened, wider than the body, orna- 

 mented with 14 cilice, equally distributed around its margin, so as to form nearly 

 a circle. Tentacles long, conical, retractile. Three pairs of short ciliae at 

 equal distances apart between the tentacles and middle of the body, connected 

 by the sharp edges of the dorsal surface. Branchial plume five parted, bipin* 

 nately divided, expanding to nearly twice the width of the body, situated a 

 little behind the middle of the body. Two short cilice close together on the 

 medium line, a little behind the branchiae. Length 1.50, breadth 0.25 inch. 

 Color yellowish, speckled with white, filaments vermilion red. 



Four specimens found on sea weed among rocks at low water near north end 

 of Catalina Island, June 16th. 



Dendronotus Alder and Hancock, 1845. 

 D. iris Cooper. State coll. species 959. 



Pale purple, varying to orange red, foot narrowly edged with white, tentacles 

 with white tips and a subterminal orange ring, branchial processes purple, the 

 smaller ones sometimes olive near the base. Length of largest specimens 3, 

 breadth 0.50 inch. 



Several found on the beach at Santa Barbara, May 5th, having been washed 

 ashore by an unusually heavy sea, occurring at a very low stage of the tide. 

 One, also, dredged on seaweed, from a depth of 28 fathoms, two miles off shore. 



This s"pecies seems more variable in color than the other nudibranchiata of 

 this coast, but I saw no reason for considering them of more than one species. 

 Those washed ashore being somewhat injured, although still alive, I made no 

 drawing of them, and the more perfect one dredged was too small for this pur- 

 pose. 



In the " Mollusca and Shells," of the U. S. Exploring Expedition under 

 Commodore Wilkes, Dr. Gould mentions a species of Dendronotus collected at 

 Puget Sound, but does not name it or give any clue to its characters, except 

 that the branchim have white tips, unlike our specimens. It is very probable, 

 however, that it belongs to the same species, as so many of the Mollusca of 

 this coast have an equally wide range. 



jEolis Cuvier, 1798. 



JE. barbarensis Cooper. State coll. species 978. 



Rose-red, longer tentacles tipped with yellow, branchial cilice simple, in six 

 longitudinal rows, all short, the middle rows longest and tipped with blue, ante- 



